When a cannon fires a cannonball we observe Newton's third law. Which is the reaction force? A) The cannon moving forward
B) The cannonball moving backward
C) The cannon moving backward
D) The cannonball moving forward

The force acting on a beam was measured under the same operating conditions and a sample of 5 data points was collected. this process was repeated by 3 observers. the pooled standard deviations of these 3 data sets was 1.21. determine the true mean force using all pooled data (with a 95% probability). the result should look like this: true mean = mean +/- margin of error